Terror expert Greg Barton says it would have been embarrassing for security forces that the Australians on an Islamic State hit list were first contacted by a Fairfax Media journalist. 
The Abbott government would not clarify whether authorities knew Australians had been compromised by the IS hack, or if those exposed in future online terror attacks would be contacted.
Despite acknowledging that IS was bolstering its online threat and that more hacks were possible, Justice Minister Michael Keenan said authorities only planned to act if a person was in potential danger.
He would not explain why Australians whose information was released by the terror group on Wednesday were not told of the hack until they were contacted by Fairfax, but said that "obviously if we felt that anybody was at risk we would have made contact with them and made sure they were protected".
Those spoken to about the hack on Wednesday expressed concern they had been told about it by a journalist, rather than the federal police or other counter-terror authorities.
Eight Australians, including Defence employees and their family members, a Victorian MP, a former army reservist, and state and federal public servants, had their information published by a group calling themselves the Islamic State Hacking Division.
Deakin University professor of global Islamic politics Greg Barton said it was likely authorities had not known that Australians were compromised until Fairfax had contacted them.
"I suspect it's an embarrassment for them that they didn't have someone looking at this," he said.
"If they had seen it, you would think that they would at least contact the employers of these people.
"There were only eight individuals, it's not a huge task."
Professor Barton said that although the information was unlikely to have been hacked using particularly sophisticated techniques, it was a clear signal of Islamic State's intent to empower their followers to perform lone wolf attacks.
A spokeswoman for Mr Keenan said he would not comment on the hack while an investigation into the hack was ongoing.
The Australian Cyber Security Centre is leading the investigation. It has already confirmed that there is no evidence to suggest the information dump was the result of any compromise of Australia-based systems or networks.
On Thursday morning, Mr Keenan backed the strength of Australia's cyber-terror capacity, despite the breach. "Our authorities of course are very good at protecting us in the online environment," he told Sky News.
Prime Minister Tony Abbott also deflected questions about the hack.
"I'll be getting more information on this over the course of the next day or so, so I'll be in a better position to answer questions about it then."
Premier Daniel Andrews said the threat to the Victorian MP was being treated seriously by Victoria Police.